Gregory was born in Paris, France, in 1934 to Russian Jewish parents. He studied at Harvard University, where he was affiliated with Adams House.
During the 1960s and 1970s, Gregory directed a number of avant-garde productions developed through ensemble collaboration, the most famous of which was Alice in Wonderland (1970), based on Lewis Carroll's two classic Alice books. He founded his own theatrical company, The Manhattan Project, in 1968. In 1975 he directed Our Late Night, the first produced play by Wallace Shawn, which began a long working relationship between the two men.
Shortly afterward, Gregory's growing misgivings about the role of theatre in modern life, and what he felt was a trend toward fascism in the United States, led him to abruptly abandon theatre and leave the country. As described in the film My Dinner with Andre (1981), he traveled to Poland at director Jerzy Grotowski's invitation, where he developed a number of experimental theatrical events for private audie...
